Apple Watch Series 4 Apple Watch Series 4, introduced on September 12, 2018, is the fourth evolution of the Apple Watch that Apple first debuted in 2015. The Series 4 models are the first Apple Watch models to feature a redesign since the Apple Watch was introduced. Available in 40 and 44mm size options, up from 38 and 42mm, Apple Watch Series 4 models feature displays up to 30 percent larger than previous models. Despite the larger displays, which flow right into the casing thanks to curved corners, the Apple Watch body has been slimmed down, so the Series 4 has a thinner, smaller case. With the bigger display, app content is easier to see than ever, and there are new complications and range of new watch faces. There's an Infograph face that supports eight complications, a Breath face for quick access to the Breathe app, and motion faces featuring Vapor, Liquid, Metal, Fire, and Water, all of which interact uniquely with the display. All Apple Watch Series 4 models feature a black ceramic and sapphire crystal backing for the first time, allowing for better cellular service because radio waves can more easily pass through the front and back. The Digital Crown includes haptic feedback for what Apple says is a more mechanical, responsive feel. Apple Watch continues to be water resistant and appropriate for use when swimming, it still supports Apple Pay, and it includes all of the health tracking features available in previous Apple Watch models, monitoring steps taken, calories burned, stairs climbed, and heart rate. There's a 50 percent louder speaker for use with Siri, phone calls, and Walkie-Talkie, and the microphone has been relocated to reduce echo. Inside, the Apple Watch features a faster, more efficient S4 chip that offers 2x the speed. Apple focused heavily on health in the Series 4 Apple Watch models, introducing a new electrical heart rate sensor that, when combined with electrodes in the Digital Crown can take an electrocardiogram (ECG) reading using a new ECG app that's coming this fall. The ECG feature can detect Atrial Fibrillation, a heart condition that is an indicator of major health conditions, and all of the ECG readings can be easily shared with a doctor. Sensors also regularly analyze heart rhythms and the Apple Watch Series 4 can send a notification if something irregular is detected. Apple has received FDA approval in the U.S. for these new features, and ECG readings are limited to the United States at this time. With a next-generation accelerometer and gyroscope, the Apple Watch Series 4 can detect if a fall occurs by analyzing wrist trajectory and impact acceleration. If motion is not detected after a fall, the Apple Watch can initiate a call to emergency services and send a message to emergency contacts. Even with all of the new features, the Apple Watch Series 4 offers 18-hour "all day" battery life, and expanded six hour battery life for outdoor workouts. The battery life has been made possible through the S4 chip and new LPTO display technology that offers improved power efficiency. Apple Watch Series 4 is available in Silver, Gold, and Space Gray Aluminum and Silver, Space Gray, and Gold stainless steel, with the latter finish being an entirely new option. There are no longer more expensive Edition models. Apple is continuing to offer both GPS and GPS + LTE models, but stainless steel models are all LTE only. Apple Watch Series 4 aluminum models are priced starting at $399 in the United States, while Aluminum GPS + LTE models are priced starting at $499. Stainless steel models are priced starting at $699. Apple is selling the Apple Watch Series 4 models with a variety of bands at varying price points, and additional bands can be purchased on a standalone basis. There are also Nike and Hermès Apple Watch Series 4 models available with unique bands and watch faces. Apple Watch Series 4 models will be available for pre-order on Friday, September 14 at 12:01 a.m. Pacific Time. An official launch will take place a week later on Friday, September 21. Nike Apple Watch Series 4 models will not launch until October 5.